Toner for developing electrostatic images

Abstract

Provided is a toner for developing electrostatic images containing a toner particle. The toner particle contains a binder resin and a release agent. The binder resin contains a vinyl resin component and a crystalline polyester resin component. The vinyl resin component has a structural unit derived from an alkyl (meth)acrylate monomer represented by Formula (1): H 2 C═CR 1 —COOR 2   Formula (1): In Formula (1), R 1 represents a hydrogen atom or a methyl group, and R 2 represents an alkyl group having 8 to 22 carbon atoms. The crystalline polyester resin component satisfies Formula (2): 5≤|C acid −C alcohol |≤12   Formula (2): In Formula (2), C alcohol represents the number of carbon atoms of the main chain of a structural unit derived from a polyhydric alcohol and C acid represents the number of carbon atoms of the main chain of a structural unit derived from a polyvalent carboxylic acid.

What is claimed is: 
     
       1. A toner for developing electrostatic images, comprising:
 a toner particle comprising a binder resin and a release agent, 
 the binder resin comprising a vinyl resin component and a crystalline polyester resin component, 
 the vinyl resin component having a structural unit derived from an alkyl (meth)acrylate monomer represented by Formula (1):
   H 2 C═CR 1 —COOR 2   Formula (1):
 
 
  where R 1  represents a hydrogen atom or a methyl group, and R 2  represents an alkyl group having 8 to 22 carbon atoms, 
 the crystalline polyester resin component satisfying Formula (2):
   5≤|C acid −C alcohol |≤12  Formula (2):
 
 
  where C alcohol  represents the number of carbon atoms of the main chain of a structural unit derived from a polyhydric alcohol forming the crystalline polyester resin component and C acid  represents the number of carbon atoms of the main chain of a structural unit derived from a polyvalent carboxylic acid forming the crystalline polyester resin component, 
 wherein the C alcohol  is 3 to 12, and the C acid  is 6 to 14, 
 the polyhydric alcohol is an aliphatic diol, and the polyvalent carboxylic acid is an aliphatic dicarboxylic acid, and 
 the crystalline polyester resin component has a melting point of 50 to 90° C., a weight average molecular weight of 5,000 to 50,000, and a number average molecular weight of 2,000 to 10,000. 
 
     
     
       2. The toner for developing electrostatic images according to  claim 1 , wherein the crystalline polyester resin component satisfies Formula (3):
   6≤|C acid −C alcohol |≤10.  Formula (3):
 
 
     
     
       3. The toner for developing electrostatic images according to  claim 1 , wherein the alkyl (meth)acrylate monomer has a branched structure. 
     
     
       4. The toner for developing electrostatic images according to  claim 1 , wherein the crystalline polyester resin component satisfies Formula (4):
   C alcohol <C acid .  Formula (4):
 
 
     
     
       5. The toner for developing electrostatic images according to  claim 1 , wherein the crystalline polyester resin component comprises a hybrid crystalline polyester resin component comprising a crystalline polyester resin segment bonded to an amorphous resin segment. 
     
     
       6. The toner for developing electrostatic images according to  claim 1 , wherein the binder resin comprises an amorphous polyester resin component. 
     
     
       7. The toner for developing electrostatic images according to  claim 6 , wherein the amorphous polyester resin component comprises a styrene-acrylic modified polyester resin. 
     
     
       8. The toner for developing electrostatic images according to  claim 1 , wherein R 2  of Formula (1) is an alkyl group having eight carbon atoms. 
     
     
       9. The toner for developing electrostatic images according to  claim 1 , wherein the toner particle has a core-shell structure comprising a core particle coated with a shell layer.